Liver cancer is a significant and increasing health concern. In the United States, there will be over 72,500 cases of colorectal cancer metastasized to the liver. Hepatocellular carcinoma (HCC) is also an increasing concern in the United States, primarily due to a rise in hepatitis C. The incidence of HCC in the United States has doubled to 17,550 cases over the last decade, and it is expected to double again over the next ten years. The vast majority of these patients will die within 5 years. The current standard for treating liver cancer is surgical resection, but only about 20% of patients are eligible for this procedure. Percutaneous radiofrequency ablation is one alternative therapy. In this therapy, a small electrode is inserted into the tumor and a high-power, high frequency electrical current heats the tumor. This therapy is a particularly attractive alternative to resection because it is inexpensive and it has a low incidence of complication. However, this therapy is only effective on small tumors-it is ineffective when treating tumors larger than 3-4 cm in diameter. A system capable of treating large tumors is critically needed since half of patients have tumors larger than 3 cm at initial diagnosis, and these larger tumors decrease life expectancy. We propose to complete the development of our saline-enhanced radiofrequency (SERF) ablation system capable of treating large liver tumors. Our system uses radiofrequency heating of tissue with simultaneous injection of hot saline through the electrode and into the tissue. The extracellular flow of saline convects the thermal energy deeper into the tissue to treat larger volumes than previously possible. Our technique has created 8 cm diameter thermal lesions in vivo. These treatment volumes are 20 times as large as those created with conventional RF electrodes. We will complete the design of our therapy system and needle and validate that it complies with medical electrical safety standards (EN60601-1), biocompatibility (ISO-10993), and validate the sterilization to a sterility assurance level (SAL) of 10(-6). We will then carry out a multi-center clinical trial at the MD Anderson Cancer Center, the University of Louisville, the University of Cincinnati and the Southwestern Medical Center. Upon completion of the clinical trial we will file and obtain 510(k) clearance to sell SERF ablation systems in the United States. [unreadable] [unreadable]